The present invention relates to power modules and, more specifically, to an integrated power package for motor control utilizing internal terminals for heat dissipation.
Power modules employing semiconductor devices are used in many different applications. One popular use for power modules is for driving and controlling motors. These power modules often use field effect transistors (FETs), particularly power metal oxide FETE (MOSFETs) to supply power to drive the motor based on signals received from a low power control circuit. While FETs are capable of switching the high currents needed to drive a powerful motor such as might be found in an automotive power steering mechanism, they also generate a significant amount of thermal energy when switching these large currents.
Large heat sinks are often used to dissipate the thermal energy generated by the FETs. This leads to large module package sizes and complicated semiconductor mounting arrangements. Also, locating the sensitive low power control circuitry close to the power semiconductors can reduce the reliability of the module and effect its operation due to the damaging thermal energy radiated by the FETs.
These module packaging requirements can be particularly onerous in automotive applications where the power module must be small and be co-located with the motor being driven. For example, a power steering electric motor driver module is optimally mounted directly to the mechanical power steering components it is driving. The presence of large heat sinks or extensive wiring and cabling between the power semiconductors and the module control circuitry is undesired as it prevents an efficient use of power semiconductor devices to control an electric motor.